(1) Field of the Invention
The present invention relates to a microwave oven and, more particularly, to a microwave oven having a door which forms a choke recess for the prevention of microwave leakage.
(2) Description of the Prior Art
Generally, a microwave oven is a cooking appliance which cooks food by frictional heat generated by making the molecules of the food being cooked move at high speeds with the use of microwaves.
Referring to FIG. 1, shown is a perspective view of a conventional microwave oven. As shown in drawing, the conventional microwave oven comprises a main body 10 defining an exterior of the microwave oven, a cooking chamber 20 having predetermined dimensions and inside of which food to be cooked is placed, and an electrical component compartment 30 provided to one side of the cooking chamber 20. Provided on a front of the microwave oven are a door 40 for opening and closing the cooking chamber 20, the door 40 being attached by hinge members (not shown), and a control panel 22 which is manipulated by the user to make various selections for the cooking of food.
The electrical component compartment 30 includes a transformer 31 for raising a level of voltage supplied from an external electric power source, and a magnetron 32 for generating microwaves using the high voltage supplied from the transformer 31 and radiating the microwaves into the cooking chamber 20.
In such a microwave oven, as microwaves are harmful to the human body, the door 40 and main body 10 of the microwave oven should be designed to prevent the leakage of these damaging microwaves from the same. Particularly, it is preferable that the microwave oven has a built-in microwave leakage-prevention mechanism. There are various techniques for preventing the leakage of microwaves, the most common of which is a choke structure provided on the door 40 of the microwave oven.
In such a choke structure, a choke recess of a given shape is formed on a predetermined area of the main body 10 or door 40 of the microwave oven. The depth of the recess is preferably 1/4 of a length of a microwave to offset the same. Such a structure acts to make an impedance at an open end of the recess infinite in magnitude, thereby restricting the leakage of microwaves.
The above choke structure will be described hereinafter with reference to FIGS. 2 and 3, which show respectively an exploded perspective view of the door of FIG. 1, and a cross sectional view taken along line III--III of FIG. 2.
The door 40 for opening and closing the cooking chamber 20 comprises an outer cover 41 having a window 41a through which food in the cooking chamber 20 can be viewed by the user, a door frame 42 having a screen 42a provided in a center portion thereof, and a bracket 43 for fixedly connecting the door frame 42 to the outer cover 41.
As shown in FIG. 3, an outer peripheral end of the door frame 42 is bent in such a manner to form a choke recess 44 for preventing the leakage of microwaves. Further, inner and outer peripheral ends 43a and 43b of the bracket 43 protrude toward the outer cover 41 to surround the recess 44. That is, the inner peripheral end 43a of the bracket 43 is inserted inside the recess 44 through an opening of the same, and the outer peripheral end 43b is fixedly inserted between the outer cover 41 and the door frame 42.
However, when assembling the door in the conventional microwave oven structured as described above, the shape of the end 42b of the door frame forming a rear side of the choke recess may become deformed by the force used in mounting the bracket 43 to the door frame and outer cover. As a result, the choke recess loses its ability to prevent the leakage of microwaves.
Further, because of the lack of such a supporting member for the bracket, it is possible for the door frame to become deformed if the bracket receives outside shock, resulting in the same problem of microwave leakage.